Spring attachment for control levers



pt- 1943- R. ATHENNING 2,329,898

SPRING ATTACHMENT FOR CONTROL LEVERS Filed Sept. 14, 1942 III-2 I I III I I M m\ v dticmzy/g Patented Sept. 21, 1943 Raymond A. Kenning, Junction City, ,0reg., as-

I signor of severity-five pe J h son i u; ,Qa i

-A'pplication semester 14, 1942, Setial-No 45s 24 FOB seme This invention'relates 'to an attachment to be applied to the steering levers of caterpillar tractors, although it is also-useful on othe'r'control levers which work'agai'nst a, stiff spring,

An object of the invention is to provide a simple, relatively inexpensive; attachment that can be. readily installed on existing control levers for facilitating the movement" of thelever through a portion of itsarc of motion.

The invention involves a particular adapta tion of what has been sometimes-referredtoas an overcenter spring: Such springs 'have :been employed on the clutch. pedal linkage of some automobiles for a number of yearsto reduce the 'force required-to depress the-clutch pedaL Without increasing the tendency of the clutch to slip when the-pedal is notl intentionally depressed. .Th'e' overcenter spring-' accomplishes this. desired result because it isso mounted.- that wherr-the clutch is engaged the spring force .actsiat-right angles to the direction of movement of the link to which it is attached, so that it exerts no effective component on the link; however, when the clutch pedal is moved out of normal position the spring exerts an increasing component in a direction efiective to aid the disengagement of the clutch. Y

The attachment of the present invention involves a spring adapted to be connected to a control lever in a similar manner so that when the lever is in one end of its swing the spring exerts force substantially radially with respect tothe axis of movement of the lever, but as the lever is moved out of the said end position the spring force is applied in such a direction as to have a component aiding the movement of the lever.

It is common practice to steer caterpillar tractors by selectivelyapplying power to the treads on the right and left sides of the machine. The usual arrangement is to connect the powe'rplant to each tread through a separate clutch and provide two levers mounted side by side for actuating the two clutches. The operator can then steer the machine to the right by pulling on the right lever, or steer it to the left by pulling on the left lever. Pulling either lever disengages its associated clutch so that the tread on that side of the machine is stopped and the driving force applied to the tread on the other side of the machine turns the machine. Simila steering arrangements are employed not only on'tractors but on tanks and other military machines employing endless tracks for their propulsion. I have found that on many of these machines the clutch prings are extremely stiff so that the with .the '.-.attachment 1;;Fig'. 2 is. a sectionaii w e along the line IIII of Fig. l.

operator. must exert substantial i' forcei. on tthe steering levers in order:tolractuateizthem; These stiff "clutch..sprin'gs; could. bizcompensatedhfor'. by building lovercenter clutch ,springs;ilsuch;ias

have. .Jpr'eviously been; referred ;to: in, connection with automobiles; Hpwevemmany- 'machines gf this .typeiarezalreacly-imtherfieldandgitlisa diffi 1 I cult. taskjto incorporate the :oyercentere springs of the prior art in these existing machin accordance. with? the present; iinventiom l developed :;anl overcenter *sp ng; .;arrangementthe steering ;levers of ,eXisting:..tractO s; andtth l s fifi tflf. reduce the force requiredgto steer he vehicle to .as'great an BXtenWaSflIlfi-MDB desire g ,i; The invention ='-W n ncws'betcxplained:ybr; fif- :scribinein detailaprefi rred mbodimen thcr o -asillustrated inthedraw n fl'w iphra; 1Q".

that :can's be 1 attached direct y;

"Fig. 1 isya side-elevation view of appntrolz and 35L '.'-f i ais nrsubstanti y There is shown in the drawing a control lever l0 having a'handle II at its upper end and being attached at its lower end' to a shaft l 2. The shaft l2 i rotatably supported in bearings l3, one only of which appears in the drawing. The shaft may be extended to any desired distance and be connected by any desired mechanical linkage with the device'that it is to be controlled by the lever It]. It will be assumed in the present instance that the shaft I2 is connected to a clutch of a tractor or the like, and that the bearing 13 is mounted on a base member Hi. It will further be assumed that when the lever is in the full line position shown in Fig. l, the clutch is fully engaged, and when the lever is swung counter-.

clockwise into the dotted line position, the clutch is disengaged. As will be readily understood the lever l0 must work against the usual clutch springs in moving from the full line to the dotted line position, and sufiicient force will have to be applied to the handle H to overcome the clutch springs. I

The attachment of the present invention com prises a bracket l5 attachable to the base l4 and carryingha pivot pin 16, arclamp ll' attachable to the lever l0 and carrying a pivot pin 18, and.

a spring assembly 19" compressible between the pivot pins It and l8. l

The bracket l5 may be formed of strap iron having a base section 20 adapted to be secured I by bolts 2| to the base member I4 of the tractor and being bent up atone end to form a vertically sectionsfi D fa'hii 32. a Q

a The crap- I"! may be formed mat-seam 21 and 28, respectively, which are clamped against opposite sides of the lever ID by a bolt 29.

The pivot pin 18 projects fromthe' clamp menr ber 21 parallel to the pivot pin 16 and to the shaft I2. I I The spring assembly includesareiativelystirr helical compression spring 30, "asleeve member 3| surrounding the upper portion of the spring,

and a core member 32 extending into tneuower 1 end of the spring and partly into the sleeveil. The sleeve 3| is pivotally secured to the pivot :pih I'G having o. ipaiis otfears 13 Whichmtrarldle tlte inember 26 and rhave'eyes to engage -the pin "at "The core: member '32 'is "formed integrally with a hub "member '33; it i is rotatab'ly mounted on 1 the pivot' l8 and detachably "secured thereto by a'walsher 35 and' oottenpin 36.'I Ther'sl'eev'e $31 the bore -32 maintai n'the "compressionvs pring 311 'in straight oondition and sprevent at them .abu gim' A t 3 l "As shown Fig; 1 the bracket is 'soxpos'rtiohed thatahepivot pin l=B' is'to th'e Ieft'df tlie lever 41] tvli'en'the latter ezttremefcl'ockwi'se position so th'at the force 'of 'the'spring 1-30 exerts a "slight clockwise bbmpon'ent of force" on Tthe lever, tendinig tb 110m 1t in normal position. Howverfiivhen 'the lever ID is manually st'viing counter-clockwise --;'a "relatively" slight :rnoverhent thereof carrle'sit-iaa'st "the' pivot R3 --a1rd "there'- after *tlie for'ce'bf the sprin'g helps to More the lv'r, rquirirfg tlre' exertion fiess strength by the operator.

-' a heen'eetwerosce-exerteu by the spring M an be varied by shifting the clamp I! upwardly or downwardly along the lever ID. This is advantageous because different operators may prefer different degrees of response to movement of the 5 lever.

It is also to be understood that the bracket l5 can be mounted in different positions to vary the osition or therpivot fs relative the normal position 'of the lever '10. 'Ifdla'sird, the pivot l-opin 16 may be positioned in alignment with the 'norrnal position of the lever l0 so that the spring "580 begins to aid the operator immediately in response to movement of the lever counter-clockwise out of normal position. 15 Tilthoughjfor "the purpose of explaining the mvenndn-a specific embodiment thereof is de- "sfibeiiin substantial detail, it is to be underrstb'o'dfth-altwafrioiis' changes can be made from the exact construction shown without departing from 20 the'ln'vention; and the latter is to be limited only to the e'leteizrtset forth-in the-appended-='claiin.

'I claim: attachment for a manual clutch *oontrol lever having ahandle onitsupperendarrd swing- 25 able in oneelirection-from a'stop rpositioirtmdisen- :gage a clutoh against the fo-rce of aolutch spring, said-attachment comprising; abracket-having ea first'pivot'elemeritmndmeans :foranchorin'gi'said bracket in stationaryposition withts'aid first :pivot 3 element substantially alongside'sai'd-leverwhen the latter isain said stop positionpsaid pivotbeing spaced substahtiallylirom the fulerumaxisof the lever, "a second {pivot means, and 'means for --de- -taohably connecting it tosaid lever atan'intermediatemoint thereon closer-to the. Euicrum of 'the l'ever than said first Ppivot means, 'and 'com- .pression spring "means interposed between said lfirs't'rind seconfi'iiivot-means for yieldably urging -said:lever "said k one direction following initial "wimovement-of the i-le've'r out of said stomposition.

'RAYMOND A. 

